Help please and thanks :)

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Step-by-step explanation:

Using the rules of exponents

⇔

=

Consider the right side

=

=

=

Now we have

9 = , that is

3² =

Since the bases on both sides are equal, equate the exponents

- 3a - 9 = 2 ( add 9 to both sides )

- 3a = 11 ( divide both sides by - 3 )

a = -

whole numbers.

step-by-step explanation:

we are given the average monthly rainfall (in millimeters) model r(m) for the years 1900-2009 as a function of the month number m.

as we can see m is taken for the number of months for years 1900-2009.

we know that number of months can't be a negative number or decimal number or a fraction.

so, the number of months could be only positive whole numbers.

therefore, whole numbers is more appropriate for the domain of r.